Preheat oven to 400 degrees F. Place 20 muffin liners in two standard 12-cup muffin pans and set aside.
In the bowl of a stand mixer fitted with the paddle attachment, combine the butter, brown sugar, spices, and salt. Cream on medium-low speed until light.
Add the eggs, one at a time, beating well after each addition. Mix in the vanilla extract.
Sift the flour, baking powder, and baking soda into a mixing bowl, and set aside.
In a large glass measuring cup or a mixing bowl, stir the buttermilk and the pumpkin puree until combined, and set aside.
Add the sifted dry ingredients to the butter mixture alternately with the liquids, in three additions. Begin and end with the dry ingredients. Scrape down the sides of your mixing bowl occasionally for even mixing.
Fill each muffin liner two-thirds full, about ⅓ cup of batter. Bake in a preheated oven for 25-30 minutes, or until the tops are golden and spring back when pressed and a wooden skewer inserted into the center comes out clean.
Cool the pumpkin muffins in the pans for about 10 minutes. Then remove the muffins from the pan and transfer them to a cooling rack to cool. Once the muffins are a little cool, it’s time for the maple glaze!